Subject: Comments on draft-ietf-l2vpn-vpls-ldp-06.txt

From: Ravindra Rathi <[email-masked]>
Date: Tue, 03 May 2005 16:33:03 +0530

1. Section 4.1.2  'Address Withdraw Message Containing MAC TLV' and
    section 4.2 'MAC Address Withdrawal'  have similar
    descriptions. They may be combined.

2. The last paragraph in Section 5.2, VPLS Learning actions,
    states that:
     -- BEGIN --
    In a basic
    VPLS case, upstream switches must insert such service delimiting
    tags. When an access port is shared among multiple customers, a
    reserved VLAN per customer domain must be used to carry STP/MSTP
    traffic. The STP/MSTP frames are encapsulated with a unique provider
    tag per customer (as the regular customer traffic), and a PEs looks
    up the provider tag to send such frames across the proper VPLS
    instance.
    -- END --

    I believe the lines quoted above should be rephrased for clarity.
    Doesn't the "service delimiting tag", "reserved VLAN per customer"
    and "unique provider tag" in the lines above refer to the same tag.

    My interpretation of the quoted lines is:
    There MUST be a service delimiting tag in _all_
    the frames received by the PE for STP/MSTP to work correctly in
    qualified mode since STP/MSTP BPDUS do not contain the
    customer vlan tag.

    Let me know if I am wrong about '_all_ the frames' part.

    I believe that 'must' in the quoted text should be replaced with
    RFC convention 'MUST'.

3. Section 5.1 says that service-delimiting tag is used to identify the vrf
    instance if it is present.

    But it doesn't explain clearly how the vrf instance is identified if the
    service-delimiting tag is not present.

    In section 5.2, couple of possibilities are discussed.
    a. For unqualified learning,  ingress port can be used to identify the
       vrf instance.

    b. For qualified learning, customer vlan and/or ingress port in the frame
       is used to identify the vrf instance.

    Text should be added to explain this clearly.

    A related question is, whether separate PWs should be setup between
    PEs per customer per customer VLAN since each of them identify a separate
    vrf instance ?

4. One minor comment. On page 2, the version numbers of all the referred drafts
    should be updated.

Thanks,
Rathi